Bay Area commuters looked skyward Tuesday morning as a gleaming white airship glided over San Francisco and the Golden Gate Bridge.
It wasn’t a blimp ad or a movie stunt — it was Pathfinder 1, a 400-foot experimental zeppelin built by LTA Research, a Silicon Valley startup backed by Google co-founder Sergey Brin.
The flight marked the latest step in Brin’s ambitious effort to reinvent lighter-than-air travel with modern materials and zero-emission technology…